The underlying theory and model of capacitive voltage substations and its associated problems are described. This system is intended to supply electricity to rural communities directly from high-voltage transmission lines. This technique leads to important cost reductions when compared with conventional alternatives. However, in several transient cases, some problems such as ferroresonance and ove...
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The unified power flow controller (UPFC) is one of the most promising flexible AC transmission systems (FACTS) devices for the load flow control. Simultaneous optimisation of location and parameters for UPFCs is an important issue when the given number of UPFCs is applied to the power system with the purpose of increasing system loadability. This paper presents a mathematical model about optimal l...
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In medium voltage (MV) power distribution network planning, especially in rural network planning, we often consider the costs of constructing a backup supply line and the resulting cost reduction for energy not supplied. A fast and simple method for this purpose is now presented. Accurate and approximate expressions for calculating the energy not supplied by a MV feeder with respect to backup supp...
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Protective current transformers (CTs) are integrated into electrical power systems for assessment of the health of the system. They are intended to provide a scaled-down value of the line current. During major faults, excessive fault currents with decaying DC components could flow through the primary of the CT, causing core saturation and a consequent malfunction of the protection system. This pro...
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An approach to identify generic dynamic equivalents to distribution systems using recurrent artificial neural networks (ANN) is presented. It is expected that in the near future a large number of active sources will be utilised within distribution systems and thus, neither detailed modelling nor lumped-load representation for distribution areas will be acceptable. Therefore, the paper suggested tr...
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A scheme for the protection of parallel transmission lines using wavelet transform (WT) has been implemented and results of experimental tests on a physical power system model are described. The relaying scheme depends on the three line voltages and the six line currents of the two parallel lines at each end. Fault detection, fault discrimination and calculation of the phasors of the measured sign...
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The embedding of advanced simulation techniques in power cables enables improved thermal protection because of higher accuracy, adaptiveness and flexibility. In particular, they make possible (i) the accurate solution of differential equations describing the cables thermal dynamics and (ii) the adoption of the resulting solution in the accomplishment of dedicated protective functions. However, the...
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This paper presents a time sequential Monte Carlo simulation technique to evaluate customer load point reliability in multi-bilateral contracts market. The effects of bilateral transactions, reserve agreements, and the priority commitments of generating companies on customer load point reliability have been investigated. A generating company with bilateral contracts is modelled as an equivalent ti...
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A method for the decentralised solution of the security constrained optimal power flow (SCOPF) problem in large interconnected power systems is presented. The method decomposes the overall SCOPF problem of a multi-area system into independent SCOPF subproblems, one for each area. The solutions of the SCOPF subproblems of the different areas are co-ordinated through a pricing mechanism until they c...
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Distribution feeder faults cause power outages, therefore it is crucial to diagnose and thus locate the fault quickly to reduce the duration of the outage. In practice, feeder patrols usually identify the fault locations by referencing the regional distribution of the calls reporting trouble, the abnormal observations of the feeders that have been reported in the calls, and the observed conditions...
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The conventional quasi-steady model of HVDC is not able to describe the dynamic switching behaviour of HVDC converters. By means of the sampled-data modelling approach, a linear time-invariant (LTI) small-signal dynamic model is developed for the HVDC main circuit in the synchronous rotating d-q reference frame. The linearised model is validated by time-domain simulation, and it can be seen that t...
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The paper presents a methodology that provides a solution for the one-day-ahead pre-dispatch problem considering the evaluation and improvement of the voltage stability margin by optimising reactive-power injections by generators and synchronous condensers. Modal participation factors are used to define penalty indices for all generators, which are then added to the optimal power flow objective fu...
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A European consortium has progressed towards a superconducting power link (SUPERPOLI) demonstration which, for the first time, combines low loss power transmission with a fault current limiter. An industrial application can be, for example, a medium voltage self-limiting power link between a generator and a high voltage transformer in a power plant. The aim is a 1 GVA range power link with a lengt...
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'Intelligent operation (IO)' can improve the reliability of a high voltage circuit breaker and prolong its life. In this paper an artificial neural network (ANN) is used in the control of circuit breaker intelligent operation. Thus, during real-time control, it can save a lot of calculating time spent in the very complicated opening process of the circuit breaker. In the design of the controller o...
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